Home >
Community >
How to fix inlet temperatures of High Temperature and Low...
Upvote
21
Downvote
+ Heterogeneous catalysis
Posted by
Muniandy Retnam
How to fix inlet temperatures of High Temperature and Low...
DearSundeep, The Process gas received from Secondary reformer contain 13 % CO which is converted to CO2 in CO shift converter by means of shift reaction. There Two or three shift converter in each plant HT, MT & LT. some plant having only HT & LT.HT temp In 360 to 380 0 C and out 430-450 0C. In MT Converter In Temp 260-2650 C and out 280 degree C. Sulphur ^ chlorine is poison of this catalyst. And in LT in Temp 190 0 C. and out 192 0 C. In HT Chromium Oxide promoted iron oxide is used in MT converter Copper chromium and Zinc based catalyst. And In LT Copper Zinc and alumina based catalyst. In order to avoid pore condensation. During the entire catalyst life the activity of more than 50 percent. Higher than that of classic iron. The high temp of any converter lead to catalyst life reduced. The catalyst life time depends upon CO slip, delta P across the bed. If the delta P increase or CO slip increase we can change the catalyst. If you increase the temp of CO shift converter bed then the bed life further deteriorate. As and when required the CO shift converter catalyst to be changed to avoid further loss in Methanator where 3/4 moles of hydrogen consumed with CO shift convert methane,As following reaction i.e. further loss, so to overcome this problem the CO shift converter catalyst must be changed timely,at high temp the catalyst start sintering. CO + 3H2 = CH4 + H2O + Heat CO2 + 4 H2 = CH4 + 2 H2O + Heat Regards, Prem Baboo
DearSundeep, The Process gas received from Secondary reformer contain 13 % CO which is converted to CO2 in CO shift converter by means of shift reaction. There Two or three shift converter in each plant HT, MT & LT. some plant having only HT & LT.HT temp In 360 to 380 0 C and out 430-450 0C. In MT Converter In Temp 260-2650 C and out 280 degree C. Sulphur ^ chlorine is poison of this catalyst. And in LT in Temp 190 0 C. and out 192 0 C. In HT Chromium Oxide promoted iron oxide is used in MT converter Copper chromium and Zinc based catalyst. And In LT Copper Zinc and alumina based catalyst. In order to avoid pore condensation. During the entire catalyst life the activity of more than 50 percent. Higher than that of classic iron. The high temp of any converter lead to catalyst life reduced. The catalyst life time depends upon CO slip, delta P across the bed. If the delta P increase or CO slip increase we can change the catalyst. If you increase the temp of CO shift converter bed then the bed life further deteriorate. As and when required the CO shift converter catalyst to be changed to avoid further loss in Methanator where 3/4 moles of hydrogen consumed with CO shift convert methane,As following reaction i.e. further loss, so to overcome this problem the CO shift converter catalyst must be changed timely,at high temp the catalyst start sintering. CO + 3H2 = CH4 + H2O + Heat CO2 + 4 H2 = CH4 + 2 H2O + Heat Regards, Prem Baboo
The normal practice when monitoring the shift reactors is to monitor the CO concentration in the effluent and calculate the shift equilibrium constant; K shift =(H2)(CO2)/(CO)(H2O) at stat of run equilibrium should be achieved at the reactor outlet as when approach to equilibrium (Keq corresponding to effluent composition equilibrium - actual T) becomes 10-20 F or greater increasing the inlet temperature to the shift reactor by 5 F or so will usually return the composition to equilibrium. The High temperature shift reactor(Fe Catalyst) is pretty rugged increasing and decreasing temperature will not significantly deactivate the catalyst. Low temperature shift catalyst (Cu based) is more sensitive increasing temperature to achieve equilibrium conditions should be done more slowly at the Low temperature shift. High Temperature shift reactors typically operate around 700 F and low temperature shift reactors operate around 400 F Let me know if you need any additional information about H2 plant monitoring best practices.
The normal practice when monitoring the shift reactors is to monitor the CO concentration in the effluent and calculate the shift equilibrium constant; K shift =(H2)(CO2)/(CO)(H2O) at stat of run equilibrium should be achieved at the reactor outlet as when approach to equilibrium (Keq corresponding to effluent composition equilibrium - actual T) becomes 10-20 F or greater increasing the inlet temperature to the shift reactor by 5 F or so will usually return the composition to equilibrium. The High temperature shift reactor(Fe Catalyst) is pretty rugged increasing and decreasing temperature will not significantly deactivate the catalyst. Low temperature shift catalyst (Cu based) is more sensitive increasing temperature to achieve equilibrium conditions should be done more slowly at the Low temperature shift. High Temperature shift reactors typically operate around 700 F and low temperature shift reactors operate around 400 F Let me know if you need any additional information about H2 plant monitoring best practices.
Thanks a lot Rick Manner Sir If I want to find Equilibrium constants for HT/LT & Primary Reformer by Simulation in Aspen Plus How should I perform it? Should I can consider Inlet temperature of HT/LT reactor for calculating Equilibrium data or outlet temperatures of reactors. Kindly can you guide for this.
Thanks a lot Rick Manner Sir If I want to find Equilibrium constants for HT/LT & Primary Reformer by Simulation in Aspen Plus How should I perform it? Should I can consider Inlet temperature of HT/LT reactor for calculating Equilibrium data or outlet temperatures of reactors. Kindly can you guide for this.
Hi sundeep, i think you need to figure out the amount (mole fraction) of the steam (vapours) in the gas entering the LT converter and find out the corresponding Dew point temperature of the gas. you must keep the inlet temperature well above the dew point temperature of the gas to ensure that moisture do not condense and end up deteriorating the catalyst of LT converter.
Hi sundeep, i think you need to figure out the amount (mole fraction) of the steam (vapours) in the gas entering the LT converter and find out the corresponding Dew point temperature of the gas. you must keep the inlet temperature well above the dew point temperature of the gas to ensure that moisture do not condense and end up deteriorating the catalyst of LT converter.
Sundeep , The equilibrium calculation is done at reactor outlet temperatures. I haven't seen Aspen Plus in many years but I assume it is similar to Aspen Hysis. Use an equilbrium reactor or a Gibbs reactor with the water gas shift reaction CO+ H2O<=> CO2+ H2 specified as the reaction and the inlet stream defined with the correct composition T and P and adjust the "approach to equilibrium" to match the data out composition from data. The approach to equilibrium should be near 0 at SOR at EOR it could as much as 10-20 F. At the plant increasing inlet temperature gradually will improve approach to equilibrium. If approach to equilibrium is originally 10 F and you increase temperatures by 5 F to achieve equilibrium at the Shift reactor outlet you have improved performance.
Sundeep , The equilibrium calculation is done at reactor outlet temperatures. I haven't seen Aspen Plus in many years but I assume it is similar to Aspen Hysis. Use an equilbrium reactor or a Gibbs reactor with the water gas shift reaction CO+ H2O<=> CO2+ H2 specified as the reaction and the inlet stream defined with the correct composition T and P and adjust the "approach to equilibrium" to match the data out composition from data. The approach to equilibrium should be near 0 at SOR at EOR it could as much as 10-20 F. At the plant increasing inlet temperature gradually will improve approach to equilibrium. If approach to equilibrium is originally 10 F and you increase temperatures by 5 F to achieve equilibrium at the Shift reactor outlet you have improved performance.
DearSundeep,
The Process gas received from Secondary reformer contain 13 % CO which is converted to CO2 in CO shift converter by means of shift reaction. There Two or three shift converter in each plant HT, MT & LT. some plant having only HT & LT.HT temp In 360 to 380 0 C and out 430-450 0C. In MT Converter In Temp 260-2650 C and out 280 degree C. Sulphur ^ chlorine is poison of this catalyst. And in LT in Temp 190 0 C. and out 192 0 C. In HT Chromium Oxide promoted iron oxide is used in MT converter Copper chromium and Zinc based catalyst. And In LT Copper Zinc and alumina based catalyst. In order to avoid pore condensation. During the entire catalyst life the activity of more than 50 percent. Higher than that of classic iron. The high temp of any converter lead to catalyst life reduced.
The catalyst life time depends upon CO slip, delta P across the bed. If the delta P increase or CO slip increase we can change the catalyst. If you increase the temp of CO shift converter bed then the bed life further deteriorate. As and when required the CO shift converter catalyst to be changed to avoid further loss in Methanator where 3/4 moles of hydrogen consumed with CO shift convert methane,As following reaction i.e. further loss, so to overcome this problem the CO shift converter catalyst must be changed timely,at high temp the catalyst start sintering.
CO + 3H2 = CH4 + H2O + Heat
CO2 + 4 H2 = CH4 + 2 H2O + Heat
Regards,
Prem Baboo
DearSundeep,
The Process gas received from Secondary reformer contain 13 % CO which is converted to CO2 in CO shift converter by means of shift reaction. There Two or three shift converter in each plant HT, MT & LT. some plant having only HT & LT.HT temp In 360 to 380 0 C and out 430-450 0C. In MT Converter In Temp 260-2650 C and out 280 degree C. Sulphur ^ chlorine is poison of this catalyst. And in LT in Temp 190 0 C. and out 192 0 C. In HT Chromium Oxide promoted iron oxide is used in MT converter Copper chromium and Zinc based catalyst. And In LT Copper Zinc and alumina based catalyst. In order to avoid pore condensation. During the entire catalyst life the activity of more than 50 percent. Higher than that of classic iron. The high temp of any converter lead to catalyst life reduced.
The catalyst life time depends upon CO slip, delta P across the bed. If the delta P increase or CO slip increase we can change the catalyst. If you increase the temp of CO shift converter bed then the bed life further deteriorate. As and when required the CO shift converter catalyst to be changed to avoid further loss in Methanator where 3/4 moles of hydrogen consumed with CO shift convert methane,As following reaction i.e. further loss, so to overcome this problem the CO shift converter catalyst must be changed timely,at high temp the catalyst start sintering.
CO + 3H2 = CH4 + H2O + Heat
CO2 + 4 H2 = CH4 + 2 H2O + Heat
Regards,
Prem Baboo
More
VOTE
The normal practice when monitoring the shift reactors is to monitor the CO concentration in the effluent and calculate the shift equilibrium constant; K shift =(H2)(CO2)/(CO)(H2O) at stat of run equilibrium should be achieved at the reactor outlet as when approach to equilibrium (Keq corresponding to effluent composition equilibrium - actual T) becomes 10-20 F or greater increasing the inlet temperature to the shift reactor by 5 F or so will usually return the composition to equilibrium. The High temperature shift reactor(Fe Catalyst) is pretty rugged increasing and decreasing temperature will not significantly deactivate the catalyst. Low temperature shift catalyst (Cu based) is more sensitive increasing temperature to achieve equilibrium conditions should be done more slowly at the Low temperature shift. High Temperature shift reactors typically operate around 700 F and low temperature shift reactors operate around 400 F Let me know if you need any additional information about H2 plant monitoring best practices.
The normal practice when monitoring the shift reactors is to monitor the CO concentration in the effluent and calculate the shift equilibrium constant; K shift =(H2)(CO2)/(CO)(H2O) at stat of run equilibrium should be achieved at the reactor outlet as when approach to equilibrium (Keq corresponding to effluent composition equilibrium - actual T) becomes 10-20 F or greater increasing the inlet temperature to the shift reactor by 5 F or so will usually return the composition to equilibrium. The High temperature shift reactor(Fe Catalyst) is pretty rugged increasing and decreasing temperature will not significantly deactivate the catalyst. Low temperature shift catalyst (Cu based) is more sensitive increasing temperature to achieve equilibrium conditions should be done more slowly at the Low temperature shift. High Temperature shift reactors typically operate around 700 F and low temperature shift reactors operate around 400 F Let me know if you need any additional information about H2 plant monitoring best practices.
More
VOTE
Thanks a lot Rick Manner Sir
If I want to find Equilibrium constants for HT/LT & Primary Reformer by Simulation in Aspen Plus How should I perform it? Should I can consider Inlet temperature of HT/LT reactor for calculating Equilibrium data or outlet temperatures of reactors. Kindly can you guide for this.
Thanks a lot Rick Manner Sir
If I want to find Equilibrium constants for HT/LT & Primary Reformer by Simulation in Aspen Plus How should I perform it? Should I can consider Inlet temperature of HT/LT reactor for calculating Equilibrium data or outlet temperatures of reactors. Kindly can you guide for this.
More
VOTE
Hi sundeep, i think you need to figure out the amount (mole fraction) of the steam (vapours) in the gas entering the LT converter and find out the corresponding Dew point temperature of the gas. you must keep the inlet temperature well above the dew point temperature of the gas to ensure that moisture do not condense and end up deteriorating the catalyst of LT converter.
Hi sundeep, i think you need to figure out the amount (mole fraction) of the steam (vapours) in the gas entering the LT converter and find out the corresponding Dew point temperature of the gas. you must keep the inlet temperature well above the dew point temperature of the gas to ensure that moisture do not condense and end up deteriorating the catalyst of LT converter.
More
VOTE
Sundeep , The equilibrium calculation is done at reactor outlet temperatures. I haven't seen Aspen Plus in many years but I assume it is similar to Aspen Hysis. Use an equilbrium reactor or a Gibbs reactor with the water gas shift reaction CO+ H2O<=> CO2+ H2 specified as the reaction and the inlet stream defined with the correct composition T and P and adjust the "approach to equilibrium" to match the data out composition from data. The approach to equilibrium should be near 0 at SOR at EOR it could as much as 10-20 F. At the plant increasing inlet temperature gradually will improve approach to equilibrium. If approach to equilibrium is originally 10 F and you increase temperatures by 5 F to achieve equilibrium at the Shift reactor outlet you have improved performance.
Sundeep , The equilibrium calculation is done at reactor outlet temperatures. I haven't seen Aspen Plus in many years but I assume it is similar to Aspen Hysis. Use an equilbrium reactor or a Gibbs reactor with the water gas shift reaction CO+ H2O<=> CO2+ H2 specified as the reaction and the inlet stream defined with the correct composition T and P and adjust the "approach to equilibrium" to match the data out composition from data. The approach to equilibrium should be near 0 at SOR at EOR it could as much as 10-20 F. At the plant increasing inlet temperature gradually will improve approach to equilibrium. If approach to equilibrium is originally 10 F and you increase temperatures by 5 F to achieve equilibrium at the Shift reactor outlet you have improved performance.
More
VOTE